This is an often covered topic. I have run 32x11.5 tires on stock rims with ant real issues. With the Toy rims, you're backspacing is likely only 3.75" instead of the Mitsu 4" BS, so you have a wider track and less interference with the frame in the rear. There are some examples of 34" Swampers on stock rims, lots of 33x10.5s and I have a Swamper 33x12.5 mounted on a stock rim as a spare. You won't have any problems with the 33s except some trimming of the front bumper ends and pushing out a little bit of the inner wheel well leading edge sheetmetal.

Have look at this thread for images and text:
Wire Thread - Biggest tires on stock rims

Russell